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rtoz writes: Last year, MIT researchers discovered that when water droplets spontaneously jump away from superhydrophobic surfaces during condensation, they can gain electric charge in the process. Now, the same team has demonstrated that this process can generate small amounts of electricity that might be used to power electronic devices. This approach could lead to devices that can charge cellphones or other electronics using just the humidity in the air. As a side benefit, the system could also produce clean water. The device itself could be simple, consisting of a series of interleaved flat metal plates. A cube measuring about 50 centimeters on a side — about the size of a typical camping cooler — could be sufficient to fully charge a cellphone in about 12 hours. While that may seem slow, people in remote areas may have few alternatives.

To be clearer: if a temperature difference can start the power generation in a humid area, can the power generated be enough to power an air conditioner to cool down enough air to extend the duration of the water condensation when the metal gets too warm and needs to be cooled? I doubt that it would allow perpetual water production but would the extra cooling allow it to extend the condensation process and power generation any significant degree?

Makes as much sense as Lucas's claim that the robots flying around on Mustafar in Revenge of the Sith are "energy collectors", collecting energy from the lava. Because they are hot, I guess. So you want to collect... the lava because it is hot.

the amount of power produced was vanishingly small â" just 15 picowatts, or trillionths of a watt, per square centimeter of metal plate. But Miljkovic says the process could easily be tuned to achieve at least 1 microwatt... per square centimeter.

This is another "5 years away" technology. I'll believe it when I see it.

Also, how did they calculate that? My phone's battery contains about 1000mAh at about 3.5V, or 3 joules. To charge that in 12 hours, you'll need 250000 square centimeters, or 50000 square centimeters per cube side, which comes out to larger than 2 meters cube.

They talk about making it smaller by having a large internal surface area, but I do not believe their fins-on-a-radiator strategy will work, since the moisture would condense near

They would need to increase the surface area of the plates, probably using three-dimensional fractals. This would increase the ratio of surface area to volume in the same way that human lungs or fish gills work.

At ~1pW/cm^2, a 50x50cm verision of this will provide about 30mWh in 12 hours. Tiny cell phone battery. Heck, a tiny lithium coin cell will provide ~150mWh.

For contrast, a typical solar cell will give 130W/m^2 (-ish), so a 0.25m^2 solar cell will provide ~33W, while the sun shines, obviously.

I'm not sure where exactly on Earth is sufficiently "remote", dark, moist, and unreachable that this makes sense. (Yes, I though of that, but it's really uncomfortable to fit a camping cooler there...)

With electrolisis and a fuel cell, only the gas carried contaminates could possibly contaminate the drinking water. For quanity and qualityproduced, I'll take the solar solution. The distances traveled and the amount produced are both quite small. In the solar solution, the volume would be much greater and due to the recombining of gasses, much less likely to transport pathagens.

They didn't - they were 'simple' water collectors (such as, I think, already exist), providing a small amount of clean water at dawn but not generating any energy in the process.
This tech, however, would be a nice one to power the Fremen's stillsuits in the same universe - providing additional water from the atmosphere while at the same time powering the various pumps and recycling tech inside of the suit:-) though if I remember correctly Herbert described those as powered by the movements of the user.

A cube measuring about 50 centimeters on a side â" about the size of a typical camping cooler â" could be sufficient to fully charge a cellphone in about 12 hours. While that may seem slow, people in remote areas may have few alternatives.

You're not going to be carrying this thing in a backpack, so it's not like you won't have a car to charge your cellphone.

On the other hand, you might be far enough out in the boonies that you can't get a car to where you are. Of course, the question then become

Arguably *something* like this could be placed remotely to power the search and rescue device at the end of a trail in a national park... It could spend months just making sure that it keeps its own battery topped of for when someone needs to signal for help.

Given that a low end cell phone charger is about 2 watts, 1 watt would be a fair performance assumption for that 50cmÂ unit. That gives us an approximate 8 watts per mÂ. Scaling up, this means that a cube 5 metres on a side will generate a kilowatt of electricity.

This new device needs a temperature differential and humidity to operate. A thermocouple only needs a temperature differential. The new device won't work anywhere where there isn't a humidity high enough to provide condensation (such as space).

It's a curiosity, but I'm not investing any money in it in the short term...

So you're telling me that when I'm outside pouring sweat in the oppressive Floridian humidity, I can look down at my phone to see it's charging and for a brief moment not hate where I live? TAKE MY MONEY!

and you can create X-rays by rapidly unrolling scotch tape in a vaccuum. I don't see conventional X-Ray machines, let alone CT scanners, leaving the scene to make way for "Scotch Tape" X-Rays. I also don't see me getting rid of my USB charging cord to make way for dehumidifier chargers. It is interesting that people have found these things out though. It gives me hope that there is still enough inquisitive nature left for true innovation.

There are ways of measuring the speed of flowing water through the small magnetic fields created from dissolved metal ions in the water. These are enough to distort the local magnetic field and allow readings to be made.

I don't know about those areas specifically, but there are many extremely poor areas of the world that are drowning in 1st world waste like plastic bottles and broken electronics.Maybe the solution could use those "resources"

Some of this already exists, like the 20oz-bottle skylight (fill bottle with water and 2 cap fulls of bleach, drill hole in tin roof, stick bottle half-way through, and seal it somehow) The end result is a bright light

Scientists have conducted simulations using super computers and whole bunch of formulas to test the impact that these devices might have on climate. Their research was inconclusive due to lack of funding but they say that it could lead to devastating planetary dryness and eventually global catastrophe. They are requesting another $10bn annually to continue the important research and have begun to lobby for Al Gore to become their fund raising spokesperson. Meanwhile a base of deniers is building who deny th

While the "water droplets spontaneously jumping off superhydrophobic surfaces" effect is interesting in itself, the mechanism of stripping charge from those droplets as they leave the apparatus sounds like a variation of the Kelvin water-drop energy harvester from 1867 [wikipedia.org]. In this case, rather than charge separation via the cross-connected cups, electric-double-layer charge-separation occurs between the droplet and the hydrophobic surface, causing the two to come away similarly unbalanced when the droplet jumps away.

Concentrated sunlight into thermal generators is more efficient, cheaper to produce, cheaper to maintain, less toxic to produce, and so on. Europe? Parabolic reflectors focus light from an infinite-distance focal point to a fixed focal point, where you place a sterling engine or a salt tower.

For the home, you don't want all that conversion waste. Electricity is the last thing you want. You should have a solar hot water system with an evacuated tube collector--a set of 18

Seriously, something like that would enable a transmitter and a camera to be set up. Where this could be useful is for fire, weather, geological monitoring. Heck, this could even be used to put simple digital telescopes up on 14K' tops and broadcast back.

I live in an area with high humidity (~80% / 25C) and am wondering how well this would work as a dehumifier that uses no electricity. The one we own is rated at 400 Wh. We often run in daily for 2+hrs. Also, if this is effective I can see other uses, like drying clothes. Or a small set up that can provide 2-3 liters of potable water/day.